Sensing ultrashort electronic coherent beating at conical intersections by single-electron pulses.

Area of Science:

• Quantum Chemistry
• Molecular Dynamics
• Ultrafast Spectroscopy

Background:

• Understanding time-dependent molecular charge densities is crucial for controlling chemical reactions.
• Existing methods struggle to capture ultrafast electronic dynamics and coupled electron-nuclear motion.

Purpose of the Study:

• To present a novel theoretical technique for probing time-dependent molecular charge densities.
• To reveal phase-sensitive, background-free coherent electron beating during conical intersection passage.

Main Methods:

• Utilizing an ultrafast optical pump to induce an electronic nonstationary state.
• Employing coherent inelastic scattering of a broadband single-electron probe pulse with variable delay.
• Spectral detection of the scattered probe pulse.

Main Results:

• Demonstrated the capability to probe time-dependent molecular charge densities.
• Successfully revealed coherent electron beating in uracil during conical intersection passage.
• Observed elusive coherent beating between strongly coupled electrons and nuclei.

Conclusions:

• The presented technique offers a powerful new tool for studying ultrafast molecular dynamics.
• Provides a pathway to observe and understand complex electron-nuclear interactions in real-time.
• Enables background-free detection of coherent phenomena in molecular systems.